How to Offset\Distribute EVENLY with PBR in Blender 2.8x?
You need to map the UVs of your mesh so that they are spaced evenly according to their dimensions. Since your mesh will map nicely onto a 2D plane. Blender can do this for you very easily.

What you had was close, but not mathematically perfect.

The best way to do it would first be to mark a seam on your mesh that will tell blender where it can start mapping, then a normal U unwrap will work (keeping the dimensions of the faces consistent). See GIF